Balls have been used for recreational activities for centuries. All sorts of ball games are played by humans, with formal or informal rules and balls that are spherical or toroidal in shape. Examples of ball games include catch, baseball, softball, football, basketball, soccer, volleyball, rugby, croquet, tennis, table tennis, etc. Balls have also been used for recreational activities with and by pets. One such game is fetch, played with dogs. Also, balls can be rolled or tossed to other animals, with the animal stopping or catching the ball. These games use balls of all sizes, sometimes as small as marbles and sometimes as large as beach balls. In general, recreational activities using balls are limited to daylight unless the playing area is artificially illuminated or the ball is illuminated.
Many illuminated balls have been proposed, with sources of illumination placed on the surface of the ball or within the interior of the ball. In the latter case, the ball is formed from a material that is at least partly transparent or translucent so that light can be transmitted from the interior through the wall. The source of illumination may be a phosphorescent material, a chemiluminescent material, or an electrical light source.
However, several problems are encountered with the manufacturing and/or use of many of the previously developed illuminated balls. If the light source can move around within the interior of the ball, it changes the weight distribution and performance of the ball while in use, and it may also damage the light source. Thus, some mechanism is generally used to hold the light source in place within the ball. Often, the ball is formed with a single spherical or toroidal exterior shell that has a tube extending into the interior of the shell for holding the light source. Most designs include end caps, springs, clamping mechanisms, and/or other retaining means to hold or apply pressure to light source and retain the source within the tube.
One example of a ball with two hemispherical shells is croquet or bocce ball described in U.S. Pat. No. 3,804,411 to Hendry. The two hemispheres mate with each other via tongue and groove features at the edges of hemispheres, and two interior tubes attached to the shells also mate with each other, such as with screw threads.
If the light source is electrical and the ball is used for activities where it is subjected to impacts, such as being thrown into the air and landing on the ground, being caught between a dog's jaws, being kicked, or being hit with a bat, mallet, or other hard object, there is a high risk that some part of the electrical system will fail. Thus, the ball and light system must be designed to minimize impact damage. Also, the ball must be designed in a way that prevents water from reaching the electrical components and causing a short circuit.
In addition to functioning reliably during long-term use, it is desirable for many applications that the ball and the light source should be inexpensive to manufacture and maintain. Further, replacement parts should be easy to obtain and install.
Thus, there is a need for an illuminated ball that is easy and inexpensive to manufacture, durable, and uses a light source that is inexpensive and easy to replace.